Originally Posted by

**detrepid** The problem I'm working on is for a boundary layer equation for an aerodynamics problem. But I'm having issues working out the partials for it, its been a long while since I've done them and I'm just not getting it to work out. Now for the problem.

I have functions:

$\displaystyle u(x,y)=Uf^{\prime}$ where $\displaystyle f^{\prime}$ is $\displaystyle \frac{\partial f}{\partial \eta}$

$\displaystyle U(x)$

$\displaystyle \eta(x,y)=yg(x)$

I need to find the following partials for my problem:

$\displaystyle \frac{\partial u}{\partial x}$, $\displaystyle \frac{\partial u}{\partial y}$, $\displaystyle \frac{\partial^{2}u}{\partial y^{2}}$, $\displaystyle \frac{\partial \eta}{\partial x}$, $\displaystyle \frac{\partial \eta}{\partial y}$, $\displaystyle \frac{\partial^{2}\eta}{\partial y^{2}}$, $\displaystyle \frac{\partial^{2}\eta}{\partial x^{2}}$, $\displaystyle \frac{\partial^{2}\eta}{\partial x\partial y}$

The second order are the ones I know I'm totally missing, the others I may be getting but it'd be nice to get a sanity check. The ones in terms of $\displaystyle \eta$ and x may cancel out when it goes back into my aerodynamics but I'm not positive of that yet.

Thanks for any help, believe me I've given this problem a solid 14 hours of head bashing yesterday before asking for help.